Food refrigeration systems, such as the conventional household refrigerator, have evolved to a high degree and the art has become quite mature. Much as been done over the decades since the now commonplace electric refrigerator was introduced commercially, providing great convenience to household or commercial users in the storage of comestibles or similar perishable items. Cooling is zoned not only between the fresh food and freezer compartments of the unit but also within the fresh food compartment as well to optimize the effective storage life of perishable edible products.
It is known that different varieties of comestibles demand different storage environments to maximize storage life. In addition to measures taken to assure adequate refrigeration temperatures, certain varieties of food products demand relatively closely regulated humidity as well; an important consideration since the circulating chilled air within the fresh food compartment of a typical refrigeration unit is ordinarily quite dry. Some food products are able to tolerate, and perhaps thrive on, low humidity cold air. Other foods require a much more controlled environment. Fresh vegetables, for example, are more or less susceptible to the desiccating effect of the chilled circulating air within a refrigerator and demand greater humidity than the relative humidity of the open food storage area. For this reason, specially constructed crisper drawers have been designed by refrigerator manufacturers and have usually been placed at or near the bottom of the fresh food compartment along with other drawers which are used for storing comestibles not as sensitive to the dry air conditions existing within the unit. Consequently, certain drawers are designed and/or designated specifically as "crisper drawers," whereas others may be designed or utilized with greater general utility in mind.
There have been attempts in the past to provide optimized environmental conditions for humidity-sensitive comestibles. For example, a humidity controlled pan assembly for a household refrigerator is disclosed in U.S. Pat. No. 4,250,719. That patent describes the worthwhile benefits of isolating sensitive foodstuffs from the desiccating effect of circulating air and the desirability of controlling humidity within an isolated compartment. That patent also describes a humidity controlled assembly including a storage pan having an open top and a stationary cover inside the refrigerator to receive the pan. A cover panel within the stationary cover may be manipulated by a moveable control mechanism and associated linkage which is used to move the cover panel back and forth along the top of the pan. The user may, accordingly, increase or decrease the amount of ventilation within the storage pan and, in turn, control the humidity therein. A conceptually similar approach is suggested in U.S. Pat. No. 4,013,434, which concerns a hydrator drawer cover with an adjustable moisture control damper. In that instance, adjustable side vents permit the user to vary the amount of moisture within a food storage drawer. The moisture level is controlled by a damper and an integral hinge pin with cooperative flexible, arcuate fingers extending through the adjustable vents. The fingers have surfaces for engaging the edge portions of the associated vents to impart positional stability thereto, for selectively rotating the damper into any one of a plurality of angularly related positions. This control facilitates circulation of ambient within the drawer. As will be appreciated from the brief description of such devices set forth above, these approaches tend to be relatively complicated from a mechanical point of view.
Other suggestions to solve the problem of ambient regulation have sought to provide a sealed enclosure for perishable comestibles without particular regard for the ability to control the humidity therein. These suggestions have centered on tightly fitting seals, approaching hermetic seals, to safeguard the environment within the storage drawer. One such approach, generally described in U.S. Pat. No. 4,173,378, utilizes a sealed food storage drawer designed for generally airtight disposition within a conventional refrigerator. The described assembly includes a one-piece frame supporting a cover panel in a locked manner with seals, suitably affixed in the side members, and a rearward member of the assembly, such that the seal extends into the path of the drawer when the drawer is moved from its open position to its closed position. Thus, when the drawer is in its closed configuration, the seal abuts the side and rear walls of the drawer. A front cross-frame member separately includes means for effecting a sealed relationship with the front wall of the drawer when it is in its closed configuration to complete the airtight environment. A similar objective is sought by the drawer tray installation described in U.S. Pat. No. 2,763,526. That patent discloses means for automatically sealing the drawer tray against the ingress of air or dust when it has been moved into its closed position in the refrigerator. That is achieved, in part, through the use of a cover plate for the drawer which is affixed in the supporting cabinet of the refrigeration unit in such a position as to overlie entirely the sliding drawer or tray when it is closed. While the drawer is in the closed position, the cover becomes engaged with the upper edges of the drawer in a snug or airtight relationship. Other patents of general or background interest along these lines include U.S. Pat. No. 1,137,073, U.S. Pat. No. 2,237,820, U.S. Pat. No. 2,306,802, and U.S. Pat. No. 3,473,345.
Viewing the foregoing patents as generally representative of the existing art, it becomes apparent that there is considerable room for improvement in the design of storage compartments which provide efficient storage of perishable comestibles. For example, those devices which seek to attain a nearly hermetic seal lose important adaptibility in the refrigerator environment because they are single purpose devices which rely on fixed sealing members. On the other hand, those approaches which admit of some measure of adjustability achieve that objective at the expense of simplicity of design; the highly complicated structural arrangements hamper not only their use and servicability but dramatically increase manufacturing costs. Thus, individually or collectively, a significant penalty is paid, ultimately by the user, in terms of the convenience and expense of the refrigeration unit itself.
Accordingly, there is a need for an improved storage compartment for perishable comestibles in a refrigeration unit which is of simple design with respect to manufacture and use, while at the same time being versatile and efficient.